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Age	Commit message (Collapse)	Author
2016-05-23	beam_type: Eliminate crash	Björn Gustavsson
	The following code: simple() -> case try 0 after [] end of 0 -> college; 1 -> 0 end. would crash the compiler like this: crash reason: {case_clause, {'EXIT', {function_clause, [{beam_type,simplify_select_val_int, [{select,select_val, {x,0}, {f,7}, [{integer,1},{f,9},{integer,0},{f,8}]}, 0], [{file,"beam_type.erl"},{line,169}]}, {beam_type,simplify_basic_1,3, [{file,"beam_type.erl"},{line,155}]}, {beam_type,opt,3,[{file,"beam_type.erl"},{line,57}]}, {beam_type,function,1,[{file,"beam_type.erl"},{line,36}]}, {beam_type,'-module/2-lc$^0/1-0-',1, [{file,"beam_type.erl"},{line,30}]}, {beam_type,module,2,[{file,"beam_type.erl"},{line,30}]}, {compile,'-select_passes/2-anonymous-2-',2, [{file,"compile.erl"},{line,521}]}, {compile,'-internal_comp/4-anonymous-1-',2, [{file,"compile.erl"},{line,306}]}]}}} The root cause is that the type representation is not well-defined. Integers could be represented in three different ways: integer {integer,{1,10}} {integer,0} However, only the first two forms were handled. To avoid similar problems in the future: * Make the type representation stricter. Make sure that integers are only represented as 'integer' or {integer,{Min,Max}}. * Call verify_type/1 whenever a new type is added (not only when merging types) to ensure that only the supported types are added to the type database). (ERL-150)
2016-05-20	beam_type: Correct handling of setelement/3	Björn Gustavsson
	We must be careful how we treat the type info for the result of: setelement(Index, Tuple, NewValue) If Tuple had type information, the result of setelement/3 (in x(0)) would be assigned the same type information. But that is not safe for: setelement(1, Tuple, NewValue) since the type for the first element will be changed. Therefore, we must take care to remove the type information for the first element of the tuple if might have been modified by setelement/3.
2015-09-28	beam_type: Improve optimizations by keeping track of booleans	Björn Gustavsson
	There is an optimization in beam_block to simplify a select_val on a known boolean value. We can implement this optimization in a cleaner way in beam_type and it will also be applicable in more situations. (When I added the optimization to beam_type without removing the optimization from beam_block, the optimization was applied 66 times.)
2015-09-28	beam_type: Improve optimization by keeping track of integers	Björn Gustavsson
	The ASN.1 compiler often generates code similar to: f(<<0:1,...>>) -> ...; f(<<1:1,...>>) -> .... Internally that will be rewritten to (conceptually): f(<<B:1,Tail/binary>>) -> case B of 0 -> case Tail of ... end; 1 -> case Tail of ... end; _ -> error(case_clause) end. Since B comes from a bit field of one bit, we know that the only possible values are 0 and 1. Therefore the error clause can be eliminated like this: f(<<B:1,Tail/binary>>) -> case B of 0 -> case Tail of ... end; _ -> case Tail of ... end end. Similarly, we can also a deduce the range for an integer from a 'band' operation with a literal integer. While we are at it, also add a test case to improve the coverage.